Tuesday, June 05, 2007


Some really weird results here, which I will discuss at the end. Media summary below followed by journal abstract:

Researchers have found the children of single mothers are more likely to grow up to be overweight or obese. The findings in the Medical Journal of Australia suggest that things such as family conflict or negative events do not have much of an impact on a child's weight.

But Lisa Gibson from the Telethon Institute for Child Health Research says the health and relationship status of their mother does. "We found that having an overweight mother or coming from a single [parent] family were the most important predictors of a child being overweight or obese," she said. Dr Gibson says it is possible single mothers do not have the time or resources to feed their children nutritious foods, or to give them exercise and recreational facilities. She says when it comes to children with an overweight mother, the link is probably a mixture of genetics and a shared environment.


Journal abstract follows:

The role of family and maternal factors in childhood obesity

By Lisa Y Gibson et al.

Objective: To investigate the relationship between a child's weight and a broad range of family and maternal factors.

Design, setting and participants: Cross-sectional data from a population-based prospective study, collected between January 2004 and December 2005, for 329 children aged 6-13 years (192 healthy weight, 97 overweight and 40 obese) and their mothers (n = 265) recruited from a paediatric hospital endocrinology department and eight randomly selected primary schools in Perth, Western Australia.

Main outcome measures: Height, weight and body mass index (BMI) of children and mothers; demographic information; maternal depression, anxiety, stress and self-esteem; general family functioning; parenting style; and negative life events.

Results: In a multilevel model, maternal BMI and family structure (single-parent v two-parent families) were the only significant predictors of child BMI z scores.

Conclusion: Childhood obesity is not associated with adverse maternal or family characteristics such as maternal depression, negative life events, poor general family functioning or ineffective parenting style. However, having an overweight mother and a single-parent (single-mother) family increases the likelihood of a child being overweight or obese.

A journal abstract is supposed to be a strictly factual summary of the full article. In this case the abstract represents the conclusions of the article but not its results. Box 2 of the full article showed that it was OVERWHELMINGLY single mothers who had fat kids. But the really odd thing is that having a fat mother had virtually NO effect on how fat the kid was. The multivariate analysis did not alter that much. What the multivariate analyses DID bring out, however, was that mothers who had never attended primary school (aborigines, most likely) were highly likely to have fat kids.

That fat mothers did not tend to have fat kids flies in the face of all previous research, however, so I think we must completely dismiss this article as based on either corrupted data, flawed analysis or hopelessly unrepresentative sampling. I am greatly surprised that it was published.

If I had been asked to referee the article I would have asked for at least the zero-order correlation matrix plus some crosstabs so that readers would have SOME hope of figuring out what was going on -- but asking me to referee ANY medical article would require a courageous editor -- given the frequency with which I detect nonsense

The stupidity of a British medical journal

The editor of "The Medical Journal of Australia" comments below on an editorial in a typically politicized British medical journal: "Australia: the politics of fear and neglect". Lancet 2007; 369: 1320. The Australian editor is too diplomatic to mention it but a journal from the home of the ever-decaying "National Health Service" lecturing Australia on its health system really is hilarious. See Matthew 7:3-5

From the first days of European settlement, our colonies were bombarded with bureaucratic edicts from the Motherland, until Federation and Australia's emergence as a proud and independent nation put an end to our dependency. But the Motherland's long-lost role was recently revived in an editorial in The Lancet entitled Australia: the politics of fear and neglect. Short, simplistic and sensational, it proclaimed that Australia's progressive and inclusive culture was burdened by a dark underbelly of political conservatism.

It further asserted that the Australian Government had effectively silenced dissent in the scientific community, and propagated a political view "that those who spoke up for indigenous health were simply `establishing politically and morally correct credentials'". To top it off, the Prime Minister was portrayed as ruthlessly exploiting Australia's strong undercurrent of political conservatism.

And The Lancet's solution? Gratuitous advice to oust the conservatives at this year's federal election and usher in a new era of "enlightenment" for Australian health and medical science!

Significantly, the editorial was silent on the concerted efforts of dedicated Australian researchers and doctors working to improve Indigenous health, and the fearless advocacy of this goal by various professional bodies and this Journal. Despite The Lancet's assertion of "silenced" scientists, its editorial was strangely silent on the conservative government's unprecedented investment in health and medical research.

Following The Lancet's edict, a commentary in The Australian warned scientific and medical journals not to engage in politics+ and put their public standing, independence and integrity at risk. As long as there remain unresolved issues in the delivery of health care to all Australians, requiring political attention and action, the MJA will never heed this injunction. But, in pursuit of this goal, the recent edict from London is hardly an example to emulate.



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.


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